Air compressor systems generate a condensate waste stream that contains oil and water. This stream is particularly generated when refrigerant-type air dryers are utilized (see, for Example, U.S. Pat. No. 4,499,033 issued to S. Basseen, et al on Aug. 9, 1988). The water is a result of the removal of moisture from the air, and the oil is a result of the lubricant used in the compressor. For example, at 75.degree. F. (23.9.degree. C.) and 75 percent relative humidity, a 500SCFM (14.2 Sm.sup.3 /min.) compressor takes in 90 gallons (340.6 liters) of water in vapor form during a twenty-four hour period. Although some of the lubricating oils are removed in other portions of the system, an undesirable amount mixes with the condensed water vapor. While the amount of oil is generally less than 2% of the stream, this significantly exceeds standards established by the U. S. Environmental Protection Agency and various other governmental agencies for disposal into sewer systems.
Oil in the water coming from a compressor system is in the form of a very fine dispersion, very much like the oil aerosols that exist in oil/air flows in systems attached to the compressor. This significantly complicates the oil/water separation. Thus, to more effectively achieve separation, the small oil droplets are permitted to coalesce (to grow together, to unite). This is usually accomplished by allowing the mixture to be quiescent for extended periods of time. A device that employs this principle is described in U.S. Pat. No. 4,684,467 issued to J. A. Cloud on Aug. 4, 1987. Usually, however, not all of the oil will coalesce particularly when the droplets are very small. Another system, as applied to the coalescence of oil in air systems, involves passing the oil/air mixture through a filter whereby the small oil aerosols bond together on the filter media to form droplets large enough to be separated and drained by gravity. While applicable for oil/gas systems, this produces excessive pressure drop for oil/water systems.
Accordingly, it is an object of the present invention to provide an oil/water separator that results in water that can be disposed of in an environmentally safe manner.
It is a further object of the present invention to provide a coalescence-type oil/water separator for adequately removing the oil from the water so as to minimize disposal costs.
It is another object of the present invention to provide a vertical coalescer to enhance separation of oil from water containing the same so that the oil concentration in the product water is sufficiently low such that the water can be easily disposed of in conventional sewer systems.
These and other objects of the present invention will become apparent upon a consideration of the drawings referred to hereinafter and a complete description thereof.